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Discussions of infant perception and cog-nition have been heating up recently

with some of the major investigators,

such as Renee Baillargeon, MarshallHaith, Andrew Meltzoff, Linda Smith,

and Elizabeth Spelke, engaged in vocal

and written debate at professional meet-ings and in issues of Infant Behavior

and Developmentand Developmental

Science15. What is the fuss about? Muchof it centers on the appropriate level of

richness of interpretation of the evi-

dence, and what kinds of skills and

knowledge can be attributed to infants,based on their performance in experi-

ments conducted with habituationdishabituation and spontaneous-pref-

erence methodologies. In accordancewith traditional constructivist views of

development, infants may be detecting

low-level stimulus variables like bright-ness and frequency, and gradually

learning to organize them by means of

experience (i.e. instruction by the envi-ronment) into more complex mental

structures that eventually attain the

status of representations. From a morenativist perspective, infants may be in-

nately possessive of deep cognitive con-

straints, which in time take the form oftheories that organize domains of

knowledge. The question is whether we

should characterize the infant as beingprimarily perceptual or intelligent.

In The Cradle of Knowledge:Development of Perception in Infancy,

an ambitious book that provides detailed

coverage and thoughtful analyses of theliterature on early perceptual devel-

opment, Philip Kellman and Martha

Arterberry offer the view that neitherthe constructivist nor nativist positions

provide apt descriptions of infant de-

velopment. Kellman and Arterberry es-pouse a different view in which infants

are, at the same time, perceptual and

intelligent because they are guidedthroughout the course of early knowl-

edge acquisition by smart perceptual

mechanisms that have evolved to extracthigher-order stimulus relationships and

produce output representations that

constitute abstract, meaningful descrip-tions of the environment. The authors

note that these descriptions can supportongoing action, but they also can be

stored and recruited for later thought

and action. The rest of cognition suchas memory, categorization, thinking, and

problem solving requires represen-

tations obtained from perceiving (p.283). The perspective is ecological, and

has its origins in the views of the early

Gestaltists, J.J. Gibsons theory of direct

perception, and E.J. Gibsons differenti-

ation model of developmental change,but it also has a modern cognitive-

science flavor (and escapes radicalGibsonianism) by invoking constructs

of mechanism and representation.

I am sympathetic to the views ofKellman and Arterberry, in particular,

to the idea that early knowledge ac-

quisition must proceed from a strongperceptual base. Such an approach to

thinking about cognition in infants is

in accordance with Robert Goldstone

and Larry Barsalous recent attempts toreunite perception and conception in

adults6. I would add that Kellman andArterberrys framework for understand-

ing perceptual development is in somerespects consistent with a form of na-

tivism that is embodied in the neural se-

lectionist views of Jean-Pierre Changeuxand Gerald Edelman. These views imply

that our evolutionary history has en-

dowed the infant with inherent sensi-tivities, perceptual preferences, and in-

formation-processing constraints, as well

as potential knowledge (i.e. categoryrepresentations and their many combi-

nations). Such species-specific biases may

account for the rapid learning observedin many of the experiments described

in this book, but without building in

innate content.Constructivism, too, offers possibil-

ities for learning complex knowledge-structures (e.g. theories) from the rep-

resentational primitives delivered by

perception (although it also needs anumber of initial constraints). For exam-

ple, the new computational analyses by

Denis Mareschal and Yuko Munakata7,8,which utilize recurrent connections to

create dynamic visual memory, may pro-

vide a mechanism for explaining howrepresentations of hidden objects can be

built up from experience with occlusion

events.Given Kellman and Arterberrys ex-

pertise in object and depth perception,

it is not surprising that the book is con-centrated in the domain of vision. But

there is also coverage of auditory per-ception, intermodal correspondence,

and the relation between perception

and action. An early chapter providesbackground on biological development

and sensory constraints, and their likely

perceptual consequences, and might beregarded as required reading for anyone

new to infant perception research. The

initial, penultimate, and final chaptersare the most provocative and offer in-

formed commentary on difficult core

issues such as the nature of perception,

Booksetcetera

443T r e n d s i n C o g n i ti v e S c i e n c e s V o l . 3 , N o . 1 1 , N o v e m b e r 1 9 9 9

The Cradle of Knowledge:Development of Perception inInfancy

by Philip J. Kellman and Martha E. Arterberry, MIT Press/Bradford Books, 1998.

$39.50 (xiv 369 pages) ISBN 0 262 11232 9

the relation between perception and

conception, and the work that remains

to be done to achieve a more completeunderstanding of perception and its

development.

Some readers might find the cover-age in the data-based chapters too de-

tailed for their tastes, but it does demon-

strate how empirical phenomena canvary, sometimes significantly, even with

slight parametric variation. The analysesof disparate experimental findings are

probing, and the authors are generous

in communicating many wise sugges-tions for further studies that might be

useful in resolving current dilemmas.

Within each chapter, periodic summariesof the conclusions that the authors draw

from sets of studies examining a com-

mon issue may prompt readers to ponderthe findings themselves and make their

own assessment of the evidence. Also, as

the book progresses, certain outcomeskeep reappearing (e.g. the importance

of motion information for represen-tation of objects and space), and majorthemes are reviewed (e.g. the develop-

mental primacy of information with the

highest ecological validity). These fea-tures provide an overall cohesiveness to

the presentation.Because there is nothing currently

quite like it, the book is well positioned

to make an immediate and significantimpact on the field of infant cognition,

an area of inquiry that will undoubt-

edly continue as one of the most activewithin cognitive science. Jacques Mehler

and Emmanuel Dupouxs What Infants

Know: The New Cognitive Science of

Early Developmentis already five years

old and has somewhat different em-

pirical and theoretical emphases9. AlanSlaters edited volume, Perceptual

Development: Visual, Auditory, and

Speech Perception in Infancy, is con-

temporary, but multi-authored, and thus

is not in a position to compete in termsof consistency of narration10.

For teaching purposes, Kellman

and Arterberrys book could be benefi-cially coupled with Alison Gopnik and

Andrew Meltzoffs Words, Thoughts, and

Theories11, in a kind of pointcounter-point contrast of bottom-up versus top-

down approaches to early knowledgeacquisition. Another option would be touse the text alongside Peter JusczyksThe Discovery of Spoken Language12,

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inasmuch as a grounding in speech is as

important as a foundation in vision forunderstanding human development.

However used, readers will benefit

from having studied Kellman andArterberrys impressive work.

Paul C. Quinn

Department of Psychology, Brown University,

Providence, RI 02912, USA.

tel: +1 401 863 2727

fax: +1 401 863 1300

e-mail: Paul_Quinn@brown.edu

References

1 Haith, M.M. (1998) Who put the cog in infant

cognition? Is rich interpretation too costly?

Infant Behav. Dev. 21, 167179

2 Meltzoff, A.N. and Moore, M.K. (1998) Object

representation, identity, and the paradox of

early permanence: steps toward a new

framework Infant Behav. Dev. 21, 201235

3 Spelke, E.S. (1998) Nativism, empiricism, and

the origins of knowledge Infant Behav. Dev.

21, 181200

4 Baillargeon, R. (1999) Young infants

expectations about hidden objects: a reply to

three challenges Dev. Sci. 2, 115132

5 Smith, L.B. (1999) Do infants possess innate

knowledge structures? The con side Dev. Sci.

2, 133144

6 Goldstone, R.L. and Barsalou, L.W. (1998)

Reuniting perception and conception

Cognition 65, 231262

7 Mareschal, D., Plunkett, K. and Harris, P.

(1995) Developing object permanence: a

connectionist model, in Proc. 17th Annu.

Conf. Cognit. Sci. Soc. (Moore, J.D. and

Lehman, J.E., eds), pp. 170175, Erlbaum

8 Munakata, Y. et al. (1997) Rethinking infant

knowledge: toward an adaptive process

account of successes and failures in object

permanence tasks Psychol. Rev. 104,

686713

9 Mehler, J. and Dupoux, E. (1994) What

Infants Know: The New Cognitive Science of

Early Development, Blackwell

10 Slater, A., ed. (1998) Perceptual Development:

Visual, Auditory, and Speech Perception in

Infancy, Taylor & Francis

11 Gopnik, A. and Meltzoff, A.N. (1997) Words,

Thoughts, and Theories, MIT Press

12 Jusczyk, P. (1997) The Discovery of Spoken

Language, MIT Press

Booksetcetera

444T r e n d s i n C o g n i ti v e S c i e n c e s V o l . 3 , N o . 1 1 , N o v e m b e r 1 9 9 9

The behavior of central nervous system

neurons depends on a complex interplay

of ionic currents of multiple sources. Thisinterplay determines how the neuron

transforms various inputs into its main

output the action potential. Under-standing the type of computations un-

derlying this inputoutput transfor-

mation often lies beyond the capacity ofour intuitive reasoning because of the

complexity of the interactions involved.

A possible approach to this problem isthat of computational neuroscience,

which integrates biophysical and mor-

phological data in computer models toinvestigate the range of complex oper-

ations taking place in neurons. This ap-

proach has become particularly interest-ing in the last 20 years or so because the

key ionic mechanisms underlying neur-onal operations have been precisely

characterized by in vitro techniques,

thereby allowing computational modelsto address questions in close relationship

to experiments.

A detailed account of this field re-quires an introduction of the basics as

well as the details of the different ionic

mechanisms that determine neuronalbehavior, such as voltage-dependent

currents, synaptic interactions, and so

forth. It also needs a clear explanationof the rationale of the different for-

malisms used for modeling these ionic

currents and how to apply them to in-vestigate specific problems, such as that

of dendritic integration. All these aspectsare treated with a remarkable clarity

by Christoph Koch in this well-written

monograph.Biophysics of Computation is orga-

nized into small chapters, each contain-

ing a relatively stand-alone description

of a specific topic, followed by a briefsummary of one page or so at the end.

The chapters are arranged in a logicalorder, starting with the basics on ionic

currents and cable theory, and consider-

ing successively more complicated issues,such as dendritic integration and spike

initiation. Indeed, one of the attractive

features of the book is that each chaptercan be consulted relatively indepen-

dently. This aspect should be particularly

appreciated by readers already familiarwith the basics, who can therefore skip

those chapters.

Throughout this tour of the field,Koch uses neocortical pyramidal neurons

as an example, and shows us a wide

range of problems that can be investi-gated using computational modeling. As

the author says, this book is not intended

to be a primer for students, because ofthe complexity of the subjects treated,

and also because the basics are relativelysuccinctly overviewed. It is more in-

tended as a reference work for advanced

graduate students and researchers in thefield of computational neuroscience, and

is also an indispensable companion for

anyone seeking to understand moreabout the biophysical interactions that

take place in neurons. Readers interested

in problems related to systems neuro-science, such as learning or sensory per-

ception, might be deceived though,

because these aspects are barely men-tioned here. However, apprehending

these problems necessarily requires a

deep understanding of issues such asdendritic attenuation, interaction of

synaptic inputs with active membranes,or the type of processing performed bydendritic spines. These subjects are

magisterially covered here and, in my

Biophysics of Computation:Information Processing inSingle Neurons

by Christof Koch, Oxford University Press, 1999. 45.00 (xxiii + 552 pages)

ISBN 019 510491 9

opinion, this is one the best overviews

of these topics presently available.On the negative side, one might

criticize the relatively narrow focus ofthe book, which essentially concentrateson single-cell or subcellular behavior,

mostly of cortical pyramidal neurons.

A lot of beautiful biophysically basedmodeling studies have been done at

the network level or at the single-celllevel for other cell types in the nervous

system, and including them would have

broadened the scope of the book. Forexample, the chapter on bursting cells

is surprisingly short although this sub-

ject was intensely studied using com-putational models, and despite the

fact that bursting plays a central role

in both vertebrate and invertebrateneurophysiology.

Fortunately though, these criticisms

do not harm the quality of the presen-tation nor the scientific value of the

work. This book should have an impor-

tant impact in making the biophysicsof neuronal behavior part of the gen-

eral knowledge that any neuroscientist

should have. Many of us would gain alot by reading it.

Alain Destexhe

Department of Physiology,

Laval University, Quebec,

Canada G1K 7P4.tel: +1 418 656 5711

fax: +1 418 656 7898

e-mail: alain@fmed.ulaval.ca